Cellulose derivative compositions



Patented 4 Sept. 8, 1936 UNITED STATES PATENT 'oFFIcE "du Pont de Nemours & Company, W Del., a corporation of Delaware No Drawing. Application August Serial No. 631,100

17 Claims.

This invention relates to cellulose derivative compositions and, more particularly, to compositions comprising a cellulose derivative and, as a plasticizer therefor, a dicarboxylic acid ester of s a monohydric ether alcohol. This application is a continuation in part of applicant's copending application Serial No. 550,286, filed July. 11, 1931, in which the general class of esters herein used as plasticizers, as wellas the preparation of such esters, is disclosed and claimed. The present invention is broader than that disclosed in app ication Serial No. 550,286 in including the "methoxy alcohol esters as plasticizers for cellulose derivatives.

An object of the present invention is to provide new cellulose derivative compositions havingadvantag'eous properties. A- further object is to provide cellulose derivative compositions adapted for use in the'coating and plastic arts and to provide compositions having improved water resistance and durability. Other objects of the invention will be apparent from the description given hereinafter. r

The above objectsare accomplished according to the .present invention by employing as a plasticizer of a cellulose derivative an ester of an aliphatic dicarboxylic acid containing from 6-10 carbon atoms; inclusive, wherein the hydrogen atom of,at leastonecarboxyl group is replaced by a group of atoms represented by the formula R. O. R'-, in which R represents the radical of a monohydric alcohol and R represents a radical frorn'the group consisting of divalent aliphatic hydrocarbon radicals and divalent aliphatic hydrocarbon radicals having analko'xy group substituted for at least one hydrogen atom thereof. ()ne or more hydrogens of thealkoxy group may be replaced by an aryl group." By alkoxy group therefore are included aralkyl ethers as well as alkyl ethers. t r v The esters herein used as plasticizers forf ellulose derivatives may be prepared by reacting a saturated or unsaturated dicarboxylic acid con- The use ofa catalyst is not esse tial, although it is preferred. Sulphuric.acid, m allic sodium,

reaction where an ester is used as the starting taining from 6-10 carbon atoms, inclusive, with a monohydric etherJalcohpl in the presence of -a catalyst at an eleyated temperature and removing of the ester used as a hydrogen chloride gas, or phenolsulphonic acid, and the like, may be used as catalysts in the reaction. The temperature may be varied widely but it is preferred to keep it between -200". C.

If desired, an inert high boiling solvent, such as i toluol, may be used in the reaction mixture to facilitate the removal of thewater formed during the reaction, or the alcohol formed during the material.

The following examples are given to illustrate the preparation of esters employed 'as plasticizers in the present invention: 7

Example 1Di-ethos:yethyl adip'ate.A mix ture of 1800 grams of adipic acid, 2500 grams of ethoxyethanol, 1000 grams of toluol, and 45 grams of sulphuric acid was heated to boiling in an apparatus designed to separate the water from the distillate and return the organic solvent to the reaction vessel. After 6 hours heating, it was found that approximately of the adipic acid had been esterified. The product was treat- 1 ed with potassium carbonate to remove the excess acid and then purified by vacuum distillation. Di-ethoxyethyl adipate distills between 200-220 C. at 10 mm. pressure.

By the use of methyladipic acid in place of adipic acid, the corresponding esters of methyl adipic acidmsy be obtained imthe manner above described By reacting butoxyethanol with methyladipic acid, the dibutoxyethyl ester.of methyladipic acid is obtained.

Example 2D i -diethylin sebacate .-A mixture containing 202 grams sebacic acid, 306 grams diethylin, grams toluol, and 4 grams sulphuric acid was heated to boiling in an apparatus such as used in Example '1. Esteriflcation was practically complete in 3 hours; The product was then purified as in Example 1. Di-diethylin s'ebaoate distiils between 260-265 C. at- 2 mm. pressure. K

' Example 3-Butozyethyl ethyl sebacate.--118 parts of butoxyethanol epntaining 0.5 part or dissolved sodi'u rn was added to 258 parts diethyl sebacate. The .mixture was-heated to boiling" -under a fractlonatingcolumn until 42 parts or ethanol had distilled out. The product was washed with water, and then purified by heating to 180 C. at 15 mm.,pressure in the presence ofdecolorizing carbon. The filtered product was an amber colored liquid.

The above example illustrates. the preparation of these esters using anester of a dicarboxylic' acid as the starting material. Arm other simple 55 ester or a dicarboxylic acid could be substituted for the ethyl ester in the above example. Likewise, any other ether alcohol can be substituted for the butoxyethanol, provided the alcohol has a higher boiling point than the alcohol formed upon hydrolysis of the dicarboxylic acid ester used as the starting material.

Example 4-Di-ethoa:yethoxyethyl adipate.- A mixture containing 150 grams of adipic acid and 325 grams of ethoxyethoxyethanol was heated to boiling for 8 hours while passing a slow stream of dry hydrogen chloride gas through the reaction mixture. The product was washed with alkali to remove the unreacted acid and then "vacuum distilled. Di-ethoxyethoxyethyl adipate distills between 250-300" C. at 6 mm. pressure.

Example 5Dz'-butoa:yethyl seb'acate.A mixture containing 202 grams sebacic acid, 350 grams butoxyethanol,'100grams toluol and 4 grams sulfuric acid was heated to boiling in an apparatus such as used in Example 1. Esterification was practically complete in three hours. The product was purified as in Example 1. Butoxyethyl sebacate distills between 240-250 C. at 2 mm.

pressure. g

The esters used as plasticizers in the cellulose derivative compositions of the present invention include the esters oi! the saturated aliphatic dicarboxylic acids having from 6-10 carbon atoms, inclusive, such as adipic, methyladipic, dimethyladipic, pimelic, suberic, azelaic, and sebacic acids, and the esters of the unsaturated aliphatic dicarboxylic acids having from 6-10 carbon atoms, inclusive, such as dihydromuconic, muconic, diacetylenedicarboxyiic, dipropargyldicarboxylio, piperyienedicarboxylic, xeronic, and tetraacetylenedicarboxylic acids. With some of those containing triple bonds care must be exercised in the preparation due to the instability of the free acids. Halogenated acids, particularly chlorinated acids, may be used. These acids may be esterifled with a monohydric alcohol represented by the formula R.O.R.OH, in which R represents a monovaient organic radical and R represents a divalent organic radical. Esters formed from the ether alcohols represented by the formula R.O.CHaCHaOH, i. e., the ether ethanois, are particularly, valuable. Besides the monohydric ether alcohols disclosed in the specific examples, butoxyethoxyethanol, benzyloxyethanol, cyclohexyloxyethanol, dodecyloxyethanol, tetrahydroturfuryloxyethanol, dibutylin, dimethylin, dibenzylin, methoxyethanol, and methoxyethoxyethanol maybe used advantageously to-esteriiy the dicarboxylic acid.

The dicarboxylic acid may be completely or partially esterifled, or may have the hydrogen atom of one carboxyl group esterifled with an ether alcohol and the other with any other monovalent organic radical, i. e., phenyl, benzyl, naphthyl, methyl, ethyl, butyl, dodecyl, cinnamyl, allyl, crotyl. cyclohexyl, tetrahydrofuriuryl, at cetera. 1 The plasticizers included within the scope of the present invention therefore comprise the half esters or acid esters, the mixed esters in which the hydrogen atom 01' at least one carboxyl group is esterifled with an ether alcohol, and the neutral esters in which the hydrogen atom of each carboxyl group is esterifled with an ether alcohol.

The herein described esters are all either water white liquids or white solids when in the pure state,'although they may be amber colored when impurities are present. They are practically insoluble in water but are readily soluble in the ordinary lacquer solvents, such as alcohols,

ketones, esters, and hydrocarbons. They are compatible in equal proportions with nitrocellulose and in somewhat lower proportions with other cellulose esters and cellulose ethers. In plastic compositions, the esters may be used in amounts up to 100%, or more, by weight of the cellulose derivative employed. Films of cellulose derivative compositions containing the neutral esters herein described are extremely tough ,and flexible and have excellent water resistance.

Due to the extremely high boiling point possessed by these esters, they impart substantially permanent flexibility to the films in which they are used. The dimethoxyethyl ester of adipic acid is particularly advantageous for use as a plasticizer in cellulose acetate compositions.

The following examples illustrate typical coating compositions containing these esters as plasticizers:

Example 6 Parts Cellulose nitrate 12.0 Pi ment 16.3 Damar 3.5 Castor oil 2.6 Dl-diethylin adipate 4.0 Solvent 161.6

Example 7 Parts Cellulose acetate 12.0 Dl-etryoxyethyl adipate 6.0 Solvent 182.0

Example 8 Parts Ethyl cellulose 4.0 Ethoxyethyl ethyl adipate 1.0 Solvent 240 Example 9 v Parts Cellulose nitrate 10.0 Di-butoxyethyl sebacate 12.0 Pigment 10.0 Solven 20.0

Example 10 Parts Cellulose ace I 12.0 Di-methoxyjthyl adipate 6.0 Solvent 182.0

Example 11 v Parts Ethyl cellulose 4.0 Methoxyethyl ethyl adipate 1.0 'Solvent 24.0

Example 12 Parts Cellulose acetate 100.0 Di-ethoxyethoxyethyl adipate" 40.0 Example 13 Parts Ethyl cellulose"; 100.0

Di-methonrethoxyethyl adipate 20.0

3. A composition comprising cell .ose acetate Example 14 K Parts Nitrocellulose 100.0 Di-diethylin sebacate 50.0 Filler (including color) 200.0

, Example 15 g Parts Cellulosee acetate 100.0 Di-methoxyethyl adipate 40.0

The above compositions-may be prepared with or without the usual volatile solvents or dilu'ents,

such as alcohols for cellulose nitrate compositions, acetone for cellulose acetatecompositions, and toluol-alcohol mixtures for the ether compositions In ,all of the above examples the plasti-' cizers may be replaced in part by other esters herein described, or by one or more of the .heretofore known plasticizers, such as triacetin, triphenyl phosphate; dibutyl phthlate, camphor, tricresyl phosphate, and the like. Other cellulose derivatives, such as cellulose propionate, cellulose butyrate, cellulose acetobutyrate, cellulose 'nitroacetate, and benzyl cellulose may be used with these esters. Likewise, other resins than damar, such as ester gum, any synthetic resins such as the polyhydric alcohol polybasic acid type, may be used. Oils other than castor, e. g., Chinawood, linseed, soya bean, or cottonseed oil, may be used.

The cellulose derivative compositions herein disclosed may be used as lacquers for coating metal leather, paper, and wood, in dopes for coat-,

ing fabrics, and in plastic compositions to be used in the preparation of toilet ware, novelties, sheeting, rods, tubes, photographic films, and in. similar uses.

The esters herein disclosed may likewise be used as plasticizers for natural resins, such as damar 'sandarac, Congo, elemi, guaiac, kauri, rosin et cetera, and synthetic resins such as polyhydric alcohol-polybasic acid r'esins, phenol-aldehyde resins, urea formaldehyde resins, vinyl resins, ester gums, and other resins; et cetera. They may be used alone or in conjunction with other modl fiers for the resins, such as waxes, and the like.

As many apparently different embodiments of this invention may be made'without departing from'the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.

I claim: Y

1. A composition comprising a cellulose derivative and an ester of an acidirom the group consisting of 'adipic, methyladipic, sebacic, and

muconic acids, wherein the hydrogen atom of each carboxyl group of the acid has been replaced by a group of atoms represented by the formula CH3OCH:CH2.

2. A composition compri ng a cellulose derivative and di-methoxyethy adipate.

lulose acetobutyrate and a diester of I 7 alkyl ether of a dihydric alcohol and sebacic acid.

and an ester of an aliphatic dicarboxylic acid containing from 6-10 .carbon atoms, inclusive, wherein the hydrogen atom .of at least onecarbdxyl group is replaced by a group of atoms represented by the formula CH:OCH2CH2, and the hydrogen atom of the remaining carboxyl group is replaced by a monovalent radical derived from an organic hydroxyl compound of the class consisting of alcohols and phenols.

4. A composition comprising cellulose acetate and di-methoxyethyl adipate.

5. A composition or matter comprising an or- Banic derivative of cellulose and a lower BB -dialkoxy diethyl adipate.

6. A composition or matter comprising cellulose acetate and a lower BB -dialkoxy diethyl adipate.

7. A composition of matter comprising cellu lose acetate and BB -diethoxy diethyl adipate.

8. A cellulose ester composition including an i organic ester of cellulose and bis-ethyl glycol sebacate. h

9. A cellulose ester composition including an organic ester of cellulose and a diester of a monoalkyl ether of a dihydric alcohol and sebacic acid. i

10. A cellulose ester composition including cellulose acetate and a diester of a monoalkyl ether of a dihydric alcohol and sebacic acid.

11. A cellulose ester composition including cel- I 12. A composition of matter comprising an organic derivative of cellulose and an alkoxyethyl ester of adipic acid.

13. A composition of matter comprising an organic derivative of cellulose and an alkoxyethyl ester of an aliphatic dicarboxylic acid containing six to ten carbon atoms, inclusive.

lulose acetate and bis-ethoxyethyl sebacate.

17. A composition of matter comprising a cellulose derivative and analiphatic dicarboxylic acid or an alkoxyalkanol 'oi' the formula RO--R"0H'wherein Ris an alkyl radical and R." is an alkylene radical of at least two car- 7 bon atoms, said acid being of the class consisting ofadipic, methyladipic, sebacic, and muconio acids.

- EMME'II'E F. IZARD.

CERTIFICATE OF CORRECTIOH.

Patent No. 2,055,289. 7 September 8, 1936.

EMMETTE F. IZARD.

It is hereby certified thalt error appeara in the printed specification of the above numbered. patent requiring correction as follows: Page 2, second A column, line 33, Example '7, for "Di-etryoxyethyl" read Di-ethoxyethyl; and

. that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed; and segled this 26th day of January A D. .1937.

Henry Van Arsdale' (Soul Acting Commi ssioner .of Patents. 

